Selection of Yeast Strains Containing β-Glucosidase for Improving Wine Aroma

Aroma is an important component for characteristic of wine. β-glucosidase is an enzyme for enhancing wine aroma during fermentation and aging. The aim of this study was to evaluate β-glucosidase activities from 17 yeast strains. It was found that strain 71 B-1122 exhibited highest activity of β-glucosidase. The purified enzyme of this strain was characterized. The purified enzyme was added in Muscat must before wine making process. The must and wine were determined for volatile compounds by headspace-SPME/GC-MS and found that the hexyl acetate, linalool, phenethyl, nerol and geraniol compounds were significantly increased after treated with the enzyme. Sensory evaluation of the combined alcoholic fermentation and flavour enrichment of Muscat juice by adding of purified β-glucosidase enzyme showed well oenological properties especially aroma. Therefore, in producing wine, yeast strain selection and addition of β-glucosidase enzyme should be considered because they were important factors affecting wine aroma.

Oleuropein-Specific-β-Glucosidase Activity Marks the Early Response of Olive Fruits (Olea europaea) to Mimed Insect Attack

Olive fruits are seriously deteriorated by pre and postharvest damage due to the attack of insects, such as Bactrocera olaea, which strongly alters the quality of olives. Defence response in olive fruits injured both by pathogens and by mechanical damages has been associated with the enzyme β-glucosidase, which specifically hydrolyses oleuropein, producing highly reactive aldehyde molecules. In situ detection of ^-glucosidase activity in olive fruit tissues following injury, which simulates Bactrocera oleae punctures, is reported. The assay was performed in two cultivars showing different degrees of susceptibilities to fly infestation. In both cultivars, the histochemical assay for β-glucosidase showed that within 20 min after the injury, a strong ^-glucosidase activity could be observed in the damaged tissues. Thereafter a progressive enzyme inactivation occurred starting from tissues around the boundary of the injury with decrease of the enzyme activity and stopped after 3 h. Whereas the mass of active cells reached a distance of （300±50） μm from the edge of the injury. Biochemical analyses showed that in extracts of the injured fruit, β-glucosidase activity rapidly increased within 20 min from injury, thereafter decreasing and reaching values comparable with those in intact fruits. Following puncture, the oleuropein contents did not change significantly in the high susceptibility cultivar, whereas it rapidly decreased in the cultivar showing low susceptibility. The results strongly suggest that olive fruits susceptible towards fly infestation could be related to the ability of the oleuropein-degrading-β-glucosidase to produce the highly reactive molecules in the damaged tissues. As a consequence of puncture, high level of peroxidase activity was detected. This feature also suggested that this enzyme could play a key role in the defence response against insect injuries.

DISTRIBUTION OF β-GLUCOSIDASE ACTIVITIES IN THE SOUTH CHINA SEA

Distribution of extracellular β-glucosidase activity (β-GlcA), bacteria abundance andTOC were investigated during tbe SCSMEX98 cruise in May and June 1998 in the South China Sea. Re-sults showed that β-GlcA varied significantly in both vertical and horizontal distribution. Hydrolysis rateranged from under detectable limit to 29% /h. In most cases, β-GlcA was highest in surface water; some-times there was a second-highest value at the bottom of the euphotic zone. Temperature controlled experi-ments showed that low temperature could significantly decrease β-GlcA; but that the low β-GlcA in

Polymorphism in the Ras andβ-Glucosidase Genes and Their Association with Growth Traits in the Pacific Oyster Crassostrea gigas

The Ras gene,a conserved member of the insulin pathway,andβ-glucosidase gene,an important cellulase,are two important growth-related genes.However,there is no study on the association between mutations of these two genes and growth traits in bivalves.Here,the polymorphism of these two genes in Crassostrea gigas were revealed.Their association with growth traits was evaluated in 290 oysters from five families,and was further confirmed in another 186 oysters from three fast-growing strains.Seventeen and twelve SNPs were identified in the Ras gene andβ-glucosidase gene,respectively.Among these SNPs,four SNPs in each gene(Ras:C.86C>A,C.90T>C,C.112A>G and C.118G>A;β-glucosidase:C.247G>A,C.284C>T,C.1260C>T and C.1293T>C)were significantly(P<0.05)associated with the growth of these oysters.Furthermore,eight and nine haplotypes were constructed in the Ras gene andβ-glucosidase gene,respectively.Oysters with both haplotypes R-Hap5(CCAA)andβ-Hap7(ACCT),or with both R-Hap 6(ATGG)andβ-Hap 6(ACTC),or with both R-Hap 6 andβ-Hap 9(ACTT),or with both R-Hap 7(ATAA)andβ-Hap 7,showed the highest growth performances.These results provide candidate markers for selecting C.gigas with fast growth.

Purification and Characterization of β-Glucosidase from a Newly Isolated Strain Tolypocladium cylindrosporum Syzx4

A higher β-glucosidase-producing strain was isolated and identified as Tolypocladium cylindrosporum syzx4 based on its morphology and internal transcribed spacer（ITS） rDNA gene sequence.The present study is to ferment,purify and characterize a β-glucosidase from T.cylindrosporum gams.The enzyme was purified to homogeneity by sulfate precipitataion,diethylaminoethyl cellulose anion exchange chromatography and Sephadex G-100 gel filtration with a 9.47-fold increase in specific activity and a recovery of 12.27%.The molecular weight（Mw） of the β-glucosidase was estimated to be 58600 by SDS-PAGE,which is much lower than that of the enzyme from other fungi.The β-glucosidase shows high activity over a wide range of temperature from 35℃ to 70℃ and the optimum pH is approximately 2.4.Then the kinetic parameters Km（0.85 mmol/L） and vmax[85.23 mmol/（L·s）] of the β-glucosidase were studied,respectively with high affinity p-nitrophenyl-β-D-glucopyranoside（p-NPG） as the substrate,inhibition constant Ki（39.5 mmol/L） with the tolerance of glucose.Although β-glucosidases have been purified and characterized from several other sources,T.cylindrosporum β-glucosidase with the unique optimal pH and higher tolerance of glucose distinguished from others makes the β-glucosidase a potential application in simultaneous saccharification and fermentation（SSF）.

Enzymatic activities and kinetic properties of β-glucosidase from selected white rot fungi

Beta-glucosidase is among the suite of enzymes produced by white rot fungi (WRF) to biodegrade plant biomass. This study investigated the enzymatic activities and kinetic properties of β-glucosidase from seventeen WRF comprised of the following species from various geographical locations: Pleurotus ostreatus, Auricularia auricular, Polyporus squamosus, Trametes versicolor, Lentinula edodes, and Grifola frondosa. All the WRF studied showed β-glucosidase activities. Significant variations in protein and carbohydrate contents were also recorded. Beta-glucosidase activities after 30 min of incubation ranged from 6.4 μg (T. versicolor) to 225 μg (G. frondosa). The calculated kinetic constant (Km) ranged from 0.47 μM (A. auricular-1120) to 719 μM (L. edodes-7). The Vmax depending on the kinetic transformation model ranged from 0.21 μg·min-1 (T. versicolor) to 9.70 μg·min-1 (G. frondosa-28). Beta-glucosidase activities also exhibited pH optima between 3.5 and 5.0 while temperature optima were between 60°C and 70°C with some media exhibiting a secondary temperature peak at 90°C attributable to the presence of thermostable isoenzyme. WRF if appropriately screened and purified can be harnessed to potentially improve the bio-conversion of cellulose to glucose and also facilitate efficient plant biomass biodegradation and production of useful plant bio-products.

Blood glucose-lowering activity of protocatechuic acid is mediated by inhibiting a-glucosidase

α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in various plant foods but also as a major microbial metabolite of dietary anthocyanins in the large colon.The present study investigated the inhibitory mechanism of PCA on a-glucosidase in vitro and examined its effect on postprandial blood glucose levels in vivo.Results from in vitro experiments demonstrated that PCA was a mix-type inhibitor of a-glucosidase.Driven by hydrogen bonds and van der Waals interactions,PCA reversibly bound withα-glucosidase to form a stable a-glucosidase-PCA complex in a spontaneous manner.The computational simulation found that PCA could insert into the active cavity of a-glucosidase and establish hydrogen bonds with catalytic amino acid residues.PCA binding aroused the steric hindrance for substrates to enter active sites and caused the structural changes of interacted catalytic amino acid residues.PCA also exhibited postprandial hypoglycemic capacity in diabetic mice.This study may provide the theoretical basis for the application of PCA as an active ingredient of functional foods in dietary management of diabetes.

Investigating the cellular functions of β-Glucosidases for synthesis of lignocellulose-degrading enzymes in Trichoderma reesei

β-glucosidases play an important role in the synthesis of cellulase in fungi,but their molecular functions and mechanisms remain unknown.We found that the 10 putativeβ-glucosidases investigated in Trichoderma ree-sei facilitate cellulase production,with cel3j being the most crucial.Transcriptional analysis revealed that the most affected biological processes in△cel3j strain were cellulase synthesis,ribosome biogenesis,and RNA poly-merases.Moreover,CEL3J was unconventionally transported through the endoplasmic reticulum,bypassing the Golgi apparatus,whereas cel3j overexpression altered cellulase secretion from conventional to unconventional,likely owing to the activated unconventional protein secretion pathway(UPS),as indicated by the upregulation of genes related to UPS.The mTORC1-GRASP55 signaling axis may modulate the unconventional secretion of CEL3J and cellulase.The transcriptional levels of genes associated with DNA replication,the cell cycle,and meiosis were noticeably affected by overexpressing cel3j.These data give new clues for exploring the roles ofβ-glucosidases and the molecular mechanisms of their unconventional secretion in fungi.

Antioxidant,antimicrobial,and α-glucosidase inhibitory activities of saponin extracts from walnut(Juglans regia L.) leaves

Objective:To investigate the relationship between triterpenoid saponin content and antioxidant,antimicrobial,and α-glucosidase inhibitory activities of 70%ethanolic,butanolic,aqueous,supernate and precipitate extracts of Juglans regia leaves.Methods:Triterpenoid saponins of different Juglans regia leaf extracts were measured by the vanillin method.Antioxidant activity was evaluated against DPPH and ABTS free radicals.We also assessed α-glucosidase inhibitory and antimicrobial activities of the leaf extracts.Pearson’s correlation coefficient was evaluated to determine the correlation between the saponin content and biological activities.Results:The butanolic extract was most effective against DPPH with an IC50of 6.63μg/mL,while the aqueous extract showed the highest scavenging activity against ABTS free radical with an IC50of 42.27μg/mL.Pearson’s correlation analysis indicated a strong negative correlation (r=-0.956) between DPPH radical scavenging activity (IC50) and the saponin content in the samples examined.In addition,the aqueous extract showed the best α-glucosidase inhibitory activity compared with other extracts.All the extracts had fair antibacterial activity against Bacillus subtilis,Escherichia coli,and Klebsiella pneumoniae except for the aqueous extract.Conclusions:Juglans regia extracts show potent antioxidant,antimicrobial,and α-glucosidase inhibitory activities.There is a correlation between saponin levels in Juglans regia leaf extracts and the studied activities.However,additional research is required to establish these relationships by identifying the specific saponin molecules responsible for these activities and elucidating their mechanisms of action.

Structural characterizations andα-glucosidase inhibitory activities of four Lepidium meyenii polysaccharides with different molecular weights

Four polysaccharides(MCPa,MCPb,MCPc,MCPd)were obtained from Lepidium meyenii Walp.Their structures were characterized by chemical and instrumental methods including total sugar,uronic acid and protein content determi-nation,UV,IR and NMR spectroscopy,as well as monosaccharide composition determination and methylation analy-ses.Four polysaccharides were a group of glucans with different molecular weights ranging from 3.12 to 14.4 kDa,and shared a similar backbone chain consisting of(1→4)-glucose linkages with branches attached to C-3 and C-6.Furthermore,bioactivity assay showed that MCPs had concentration-dependent inhibitory activity onα-glucosidase.MCPb(Mw=10.1 kDa)and MCPc(Mw=5.62 kDa)with moderate molecular weights exhibited higher inhibitory activ-ity compared with MCPa and MCPd.

Ethanol extract of Annona muricata Linn fruit perform antidiabetic effect on type 2 diabetic mice through α-glucosidase inhibition

Objective:To explore the anti-diabetic effects and its underlying mechanism of Annona muricata Linn fruit ethanol extract(AME).Methods:Streptozotocin-induced type 2 diabetic(T2DM)mouse model was constructed.Those diabetic mice were randomly grouped and given 50 mg/kg acarbose or AME(200 mg/kg,100 mg/kg or 50 mg/kg)for four weeks.The body weight,postprandial blood glucose and glycosylated hemoglobin levels were measured during the administration.After the administration,a glucose tolerance test was performed,and the levels of triglycerides,cholesterol and low-density lipoproteins in mice were detected by biochemical test kits.The inhibitory activity of AME onα-glucosidase in vivo and in vitro was determined by enzyme inhibition tests.Results:AME significantly reduced weight gain,postprandial blood glucose,glycosylated hemoglobin and low-density lipoprotein levels in T2DM mice;enhanced glucose tolerance and pancreaticβ-cell function of T2DM mice;inhibitedα-glucosidase activity in mouse intestine in an noncompetitive manner.Conclusion:AME may noncompetitive inhibitα-glucosidase activity and reduce postprandial glucose intake to achieve a therapeutic and regulatory effect on type 2 diabetes.

Gene Cloning and Molecular Characterization of a β-Glucosidase from Thermotoga Naphthophila RUK-10：an Effective Tool for Synthesis of Galacto-oligosaccharide and Alkyl Galactopyranosides

A novel thermostable β-glucosidase（Tnap0602） with β-galactosidase activity was cloned from Thermotoga naphthophila RUK-10 and overexpressed in Escherichia coli BL21（DE3） with the aid of pET28b（＋） vector. The recombinant β-glucosidase was purified to homogeneity by heat precipitation and Ni^2＋-affinity chromatography. The molecular weight of the recombinant enzyme was estimated to be 51 kDa by SDS-PAGE analysis. The optimum temperature for the hydrolyses of p-nitrophenyl-β-D-glucopyranoside and o-nitrophenyl-β-D-galactopyranoside by the recombinant β-glucosidase were both above 95 ℃, and the corresponding optimum pH value was found to be the same as 7.0. Thermostability studies show that the half-lives of the recombinant enzyme at 75, 80, 85 and 90℃ are respectively 84, 32, 14, and 3 h, and it is quite stable in a pH range of 5.0-10.0. The Km and Vmax values of the recombinant β-glucosidase for the hydrolysis of pNPGlu at 80 ℃ are 0.127 mmol/L and 18389.1 μmol·min^1·mg^-1, the corresponding values are 0.625 mmol/L and 6250 μmol·min^1·mg^-1 for the hydrolysis of oNPGal, respectively, The enzyme also display the hydrolysis activity for lactose and cellobiose. Galacto-oligosaccharide and alkyl galactopyranosides could be synthesized from Tnap0602 when lactose was used as the transglycosylation substrate, indicating that the thermostable β-glucosidase could be a candidate for industrial application.

α-Glucosidase Inhibitors from Glycyrrhiza uralensis Fisch.

Aim To screen for α-glucosidase inhibitor from Glyeyrrhiza uralensis Fisch.. Methods Glycyrrhizic acid, glycyrrhetinic acid, flavonoids of glycyrrhiza, alkaloids of glycyrrhiza, and glycyrrhiza polysaccharides were isolated from the root of Glycyrrhiza uralensis Fisch. respectively. Three compounds were isolated from the flavonoids of glycyrrhiza as guided by the α-glucosidase inhibitory test in vitro. Moreover, the characteristics of inhibitory kinetics of glycyrol and glycyrrhetinic acid were investi- gated. Results The flavonoids of glycyrrhiza and glycyrrhetinic acid had the strongest α-glucosidase inhibitory activity. Glycyrol,β-sitosterol and liquifitin were isolated and identified. Glycyrol was a fast- binding, reversible, noncompetitive α-glucosidase inhibitor, showing IC50 at 0.26 μg·mL^-1 Glycyrrhetinic acid was a fast-binding, irreversible α-glucosidase inhibitor, showing IC50 at 102.4 μg·mL^-1. Conclusion Glycyrol is an effective α-glucosidase inhibitor.

Characterization of β-glucosidase from Aspergillus terreus and its application in the hydrolysis of soybean isoflavones

An extracellular β-glucosidase produced by Aspergillus terreus was identified, purified, characterized and was tested for the hydrolysis of soybean isofiavone. Matrix-assisted laser desorption/ionization with tandem time-of- flight/time-of-flight mass spectrometry （MALDI-TOF/TOF MS） revealed the protein to be a member of the glycosyl hydrolase family 3 with an apparent molecular mass of about 120 kDa. The purified 13-glucosidase showed optimal activity at pH 5.0 and 65℃ and was very stable at 50℃. Moreover, the enzyme exhibited good stability over pH 3.0-8.0 and possessed high tolerance towards pepsin and trypsin. The kinetic parameters Km （apparent Michaelis- Menten constant） and Vmax （maximal reaction velocity） for p-nitrephenyl-β-D-cjlucopyranoside （pNPG） were 1.73 mmol/L and 42.37 U/mg, respectively. The Krn and Vmax for cellobiose were 4.11 mmol/L and 5.7 U/mg, respectively. The enzyme efficiently converted isoflavone glycosides to aglycones, with a hydrolysis rate of 95.8% for daidzin, 86.7% for genistin, and 72.1% for glycitin. Meanwhile, the productivities were 1.14 mmol/（L.h） for daidzein, 0.72 mmol/（L.h） for genistein, and 0.19 mmol/（L.h） for glycitein. This is the first report on the application of A. terreus β-glucosidase for converting isoflavone glycosides to their aglycones in soybean products.

A simplified and miniaturized glucometer-based assay for the detection of β-glucosidase activity

β-Glucosidase activity assays constitute an important indicator for the early diagnosis of neonatal necrotizing enterocolitis and qualitative changes in medicinal plants.The drawbacks of the existing methods are high consumption of both time and reagents,complexity in operation,and requirement of expensive instruments and highly trained personnel.The present study provides a simplified,highly selective,and miniaturized glucometer-based strategy for the detection ofβ-glucosidase activity.Single-factor experiments showed that optimumβ-glucosidase activity was exhibited at 50°C and pH 5.0 in a citric acid-sodium citrate buffer when reacting with 0.03 g/mL salicin for 30 min.The procedure for detection was simplified without the need of a chromogenic reaction.Validation of the analytical method demonstrated that the accuracy,precision,repeatability,stability,and durability were good.The linear ranges ofβ-glucosidase in a buffer solution and rat serum were 0.0873–1.5498 U/mL and 0.4076–2.9019 U/mL,respectively.The proposed method was free from interference fromβ-dextranase,snailase,β-galactosidase,hemicellulase,and glucuronic acid released by baicalin.This demonstrated that the proposed assay had a higher selectivity than the conventional dinitrosalicylic acid(DNS)assay because of the specificity for salicin and unique recognition of glucose by a personal glucose meter.Miniaturization of the method resulted in a microassay forβ-glucosidase activity.The easy-to-operate method was successfully used to detect a series ofβ-glucosidases extracted from bitter almonds and cultured by Aspergillus niger.In addition,the simplified and miniaturized glucometer-based assay has potential application in the point-of-care testing ofβ-glucosidase in many fields,including medical diagnostics,food safety,and environmental monitoring.

Antioxidant,flavor profile and quality of wheat dough bread incorporated with kiwifruit fermented byβ-glucosidase producing lactic acid bacteria strains

This study aimed to investigate the effect of incorporation of kiwifruit substrate fermented by 3 highβ-glucosidase producing lactic acid bacteria(LAB)of Lactobacillus harbinensis(M12,M24)and Pediococcus pentosaceus(J28)on physicochemical and rheo-fermentation properties during proofing of wheat dough.Quality,sensory evaluation,antioxidant content and activity,and flavor profiles of bread was evaluated.Results revealed that LAB strains adequately adapted(J28>M12>M24)and produced enzymes during substrate fermentation.In dough,incorporation of fermented substrate increased acidity,soluble dietary fiber,β-glucosidase andα-amylase activity and gas retention during proofing,in a strain dependent manner(J28>M12>M24).The subsequent breads exhibited higher specific volume and had softer crumbs.Furthermore,total flavonoid,total phenolic,antioxidant activity,flavor content and intensity increased in breads incorporated with fermented substrate.Overall sensory acceptance was in order,bread containing substrates fermented by J28(KFB-J28)>M12(KFB-M12)>M24(KFB-M24)>wheat bread(WB)>bread containing unfermented substrate(KFB).Changes observed were attributed to biotransformation byβ-glucosidase which increasingly degraded dietary fibers into soluble dietary fiber,increased acidity,released glycosylated aroma compounds and phenolic compounds in substrate.When incorporated in dough,fermented kiwifruit substrates stabilized gluten network,increased yeast metabolism and gas retention during proofing.Subsequently,KFB-J28,KFB-M12,and KFB-M24 had higher antioxidant content and activity,higher flavor content and intensity,better quality and were more accepted compared to WB and KFB.This suggested the potential role played byβ-glucosidases through LAB fermentation on functionally enriching and adding value to kiwifruit substrate as a novel functional ingredient in bakery industry.

Short-term effects of maize residue biochar on kinetic and thermodynamic parameters of soil β-glucosidase

Soil β-glucosidase (BG), the rate-limiting enzyme in the final step of cellulose hydrolysis, plays a key role in microbial metabolism, carbon (C) cycling and sequestration in terrestrial ecosystems. Biochar application is known to affect soil BG activity;however, most of the biochar studies have focused on the potential activity of BG, and it is not clear how biochar influences the kinetic and thermodynamic behavior of BG in the soil. The objective of this study was to investigate the effect of maize residue biochar on soil BG kinetic and thermodynamic parameters. Soil BG kinetic (V_(max) and K_(m)) and ther-modynamic (E_(a), ΔH_(a) and Q_(10)) parameters were determined within soils (clayey and sandy loam soils) amended with either maize residue (as positive control) or its biochar (600℃) at 0.5 and 1.0% ratios (w/w), and the mixtures were incubated for 90 days. BG showed an increase in potential enzymatic activity (81%), enzyme concentration (higher V_(max) value) (25%) and substrate affinity (lower K_(m) value) (32%) in the biochar-amended sandy loam soil only at high addition rates compared with the control, and an increase by about 86% of the catalytic efficiency (V_(max)/K_(m)). In the clayey soil, biochar addition decreased potential BG activity (by 10-29%), increased the V_(max) value (by 20-25%) and had no impact on enzyme-substrate binding affinity, but still increased the catalytic efficiency by 47-72%. Adsorption of soil BG by biochar particles did not affect the catalytic efficiency in the soil. Generally, application of maize residue biochar to the soil decreased the E_(a), ΔH_(a) and Q_(10) values of BG compared with the negative controls at both biochar rates in the light-textured soil and only at low biochar rate in heavy-textured soil. The direction and magnitude of BG responses (activity, kinetics, and thermodynamics) to biochar were more related to the soil characteristics. Biochar would increase soil BG thermal stability and decrease its sensitivity to increasing temperature and global warming.

Effects of α-glucosidase Inhibitors on the Function of Mulberry Leaf Extract as an Additive in Feedstuff

The mulberry juice contains high concentrations of α-glucosidase inhibitors that affect glycometabolism and cause diarrhea in animals, thereby affecting the de-velopment and application of mulberry （Morus alba L.） as feedstuff resources. ln this study, the effects of mulberry leaf extract with and without removal of mulberry juice on starch metabolism were analyzed and compared. The results showed that mul-berry leaf extract with removal of mulberry juice exhibited significantly lower inhibi-tion rate on starch metabolism compared with mulberry leaf extract without removal of mulberry juice. ln animal feeding trials, piglet feedstuff was added with 10% mul-berry leaf powder; compared with mulberry leaf powder without removal of mulberry juice, experimental piglets fed with mulberry leaf powder with removal of mulberry juice exhibited significantly improved weight gain and significantyl reduced diarrhea rate.

Expression of heat-resistant β-glucosidase in Escherichia coli and its application in the production of gardenia blue

Gardenia blue is a natural blue pigment that is environmentally friendly,non-toxic,and stable.The hydrolysis of geniposide,catalyzed byβ-glucosidase,is a critical step in the production process of gardenia blue.However,β-glucosidase is not resistant to high temperatures,limiting the production of gardenia blue.In this study,we investigated the effectiveness of a heat-resistant glucosidase obtained from Thermotoga maritima in the production of gardenia blue.The enzyme exhibited a maximum activity of 10.60 U/mL at 90℃.Single-factor and orthogonal analyses showed that exogenously expressed heat-resistant glucosidase reacted with 470.3μg/mL geniposide and 13.5μg/mL glycine at 94.2℃,producing a maximum yield of 26.2857μg/mL of gardenia blue after 156.6 min.When applied to the dyeing of denim,gardenia blue produced by this method yielded excellent results;the best color-fastness was achieved when an iron ion mordant was used.This study revealed the feasibility and application potential of microbial production of gardenia blue.

Characterization of purified <i>β</i>-glucosidase produced from <i>Trichoderma viride</i>through bio-processing of orange peel waste

In the present study, solid state fermentation was carried out using orange peel waste to produce β-glucosidase from Trichoderma viride. A locally isolated fungal strain T. viride was cultured in the solid state medium of orange peel (50% w/w moisture) under optimized fermentation conditions and maximum activity of 515 ± 12.4 U/mL was recorded after 4th day of incubation at pH 5.5 and 30℃. Indigenously produced β-glucosidase was subjected to the ammonium sulfate precipitation and Sephadex-G-100 gel filtration chromatography. In comparison to the crude extract β-glucosidase was 5.1-fold purified with specific activity of 758 U/mg. The enzyme was shown to have a relative molecular weight of 62 kDa as evidenced by sodium dodecyl sulphate polyacrylamide gel electrophoresis. The purified β-glucosidase displayed 6 and 60℃ as an optimum pH and temperature respectively.